1. Field of the Invention
The present invention pertains to the field of diagnostic and therapeutic medical devices and procedures. More particularly, the present invention relates to the field of stabilization, imaging and procedure facilitating platforms for the female breast.
2. Description of the Related Art
Women aged 40 and over are recommended to undergo an annual screening mammogram to potentially identify a breast cancer in its most early stages of development. By definition, these women are asymptomatic and the lesions within their breasts, if any, are most often non-palpable. Most small breast cancers are, therefore, diagnosed by screening mammography. To obtain an acceptable mammographic image, the breast must be compressed and held immobile between two parallel plates. Compression is mandatory to obtain the required mammographic views, as an adequate mammogram cannot be obtained unless the breast is in compression. Conventionally, a computer calculates the x, y and z coordinates targeting the lesion and a biopsy instrument is then inserted within the compressed breast to biopsy the lesion.
Because of the required compression, the placement of the compression plates on the woman's breast determines the skin entry site for the procedure and, therefore, the location of the resulting scar. Indeed, the position of the breast in the compression device dictates where the incision is to be made. Conventionally, the scar is most always on the side of the breast, whether superior, lateral, inferior or medial. The scar can range from about 5 mm in length to an unsightly 3 cm if a large coring device is used.
Examples of such devices and methods include that disclosed in U.S. Pat. No. 5,702,405 issued Dec. 30, 1997 to Heywang-Koebrunner. As described in this reference, the breast is compressed between two plates of a stereotactic attachment to a tomography device. Through holes are disposed in one of the two compression plates at an oblique angle within a plane that is substantially perpendicular to the plane of the plates, to allow a biopsy needle to access the breast through the side thereof. Similarly, U.S. Pat. No. 4,563,768 to Read et al. discloses a mammographic device utilizing two parallel plates to compress the breast. One of the compression plates functions as an X-ray film holder. A matrix of perforations is disposed in one the compression plates, allowing access to the side of the breast by a biopsy needle or the like. U.S. Pat. No. 4,691,333 uses similar breast compression and side access technology. LaBash, in U.S. Pat. No. 5,499,989 discloses yet another breast compression scheme, in which the breast is stabilized by compression, whereupon a guide spool is aligned over an opening in one of the plates. The guide spool guides a tubular punch or a biopsy needle through the breast to the lesion site, puncturing the side of the compressed breast.
These and other similar devices share a number of disadvantages. When the lesion is biopsied with the breast in compression, the cavity left after the biopsy procedure expands as the breast is uncompressed after the procedure. This expanded cavity can cause unsightly disfigurements, particularly when large coring devices are used. It would be advantageous, therefore, to perform the biopsy procedure on an uncompressed breast. However, localization of small breast lesions has conventionally required mammographic imaging. Mammographic imaging, in turn, requires that the breast remain compressed.
Ultrasound imaging is currently used with good results for specific indications, but is generally not used as a screening modality. Indeed, ultrasound is conventionally used to gather additional information about a suspicious area seen on mammography, or about a palpable lesion. Conventionally, it has been difficult to determine conclusively that a suspicious area as seen by ultrasound correlates exactly with that seen during the mammogram. In addition, suspicious microcalcifications seen by mammography are not readily visualized by ultrasound imaging techniques currently available. Therefore, ultrasound conventionally has been of little help in biopsying or excising small, non-palpable cancers or suspicious areas.
In instances where surface ultrasound is effective in localizing a lesion, a manual biopsy procedure may be carried out under surface ultrasonic guidance. In such a directed biopsy procedure, the lesion within the breast is sonographically targeted and a fine needle aspiration, core biopsy or vacuum-assisted core biopsy procedure is carried out. In such a procedure, the breast is not compressed and a surface ultrasound transducer is typically used to image the breast and the site of interest therein. In surface ultrasound-guided biopsy, the physician must manually (i.e., by placing a hand on the breast) stabilize the breast as best as possible, hold the ultrasound probe, and perform the biopsy accurately enough to obtain tissue from the lesion. Conventionally, this procedure is carried out by inserting the needle within the breast in an orientation that is as near parallel to the patient's chest wall as possible. The breast stabilization, the operation of the probe, as well as the actual needle biopsy must be carried out simultaneously, all the while maintaining the needle within the focal plane of the ultrasound probe. It is difficult to have an assistant help perform the procedure because if the ultrasound probe and/or needle are not exactly in line and are off by a fraction of a millimeter, then the needle cannot be visualized on the ultrasound monitor. Moreover, any movement of the patient (e.g., coughing, shifting) will also cause the biopsy device and surface ultrasound probe to misalign.
Carrying out biopsy procedures on the uncompressed breast would alleviate the disadvantages associated with compressing the breast. Importantly, such procedures on the uncompressed breast would be less painful, would allow more choices for the entry site, would reduce the size of the cavity left after the excisional procedure and would provide a means for excising tissue from the breast in its natural state.